As many as one in three people will be dead within 24 hours of
having a heart attack. But most people who survive the first month
will still be alive five years later. So prompt treatment is
essential, as is prevention.

What causes a heart
attack?The heart is a large muscular pump. It beats 70 times
a minute to push blood around the body. Like any busy muscle, the
heart tissues need a good supply of blood from their blood vessels,
which are called the coronary arteries.

Diseases that narrow
the coronary arteries can cause a shortage of oxygen and essential
nutrients in the heart muscle.

This triggers chest pain known
as angina, especially when the heart is made to work extra hard, for
example during exercise. If someone has angina, the more severe the
narrowing of the arteries, the less they can do before they
experience pain.

If the shortage is severe and prolonged,
some of the heart muscle will die, resulting in permanent damage.
This is a heart attack, more technically known as a myocardial
infarction or MI.

Blocked coronary arteriesThe
most common underlying disease for heart attacks is atherosclerosis,
where fatty plaques build up on the lining of the coronary arteries.
This is known as coronary artery disease, and is a gradual process
that slowly limits the blood supply to the heart muscle.

How do
heart attacks happen?What usually happens in a heart attack
is that one of the fatty plaques cracks and a blood clot forms on
top of it. It is this clot that finally blocks the artery
completely.

There are other, rarer causes of a heart attack,
such as a dissection or splitting of the wall of the coronary
artery.

How many people are affected?The UK has
one of the worst heart attack rates in the world. It's estimated
that someone has a heart attack every two minutes in the UK. More
than 1.4 million people have angina and each year about 275,000
people have a heart attack. Of these, more than 120,000 are
fatal.

Heart attacks are responsible for one in four deaths
in men and one in six deaths in women. They are more common among
older people.

Risk factorsThe biggest single risk
factor for heart attack is smoking. Other causes include high
cholesterol, high blood pressure, diabetes and a family history of
heart disease.

There are many steps you can take to change
your lifestyle and reduce your risk.

Different types of
heart attackWhen someone goes into hospital with pain or
other symptoms suggesting coronary heart disease, a diagnosis of
acute coronary syndrome (ACS) is made.

The next step is to
work out which part of the heart is affected, and how badly. This is
done by studying an electrocardiogram (ECG) and other tests, in
particular a blood test that measures levels of a chemical called
troponin, which is released from damaged heart muscle
cells.

There are several different types of heart attack. The
area of the heart that's affected has important implications for
what sort of complications there may be, how well the patient will
recover and the treatment they should be given.

For example,
if a heart attack affects the inferior (underneath) surface of the
heart, which sits against the diaphragm, there is a greater risk of
abnormal heart rhythms, because the electrical conducting system of
the heart is disrupted.

If the heart attack affects the
anterior (front wall) of the heart, there is more likely to be
damage to the left ventricle, which is responsible for pumping blood
around the body, leading to low blood pressure and heart
failure.

Sometimes a heart attack doesn't affect the full
thickness of the heart muscle and may not produce typical changes on
an ECG. This sort of heart attack may require different
treatment.

Rapid treatment saves livesAbout half
of those who have a heart attack die within 28 days. Most people who
survive the first month will still be alive five years later, but
many are left with long-term heart problems.

One in three
people dies within 24 hours. Most of these deaths are sudden,
occurring within one hour of onset of symptoms and before reaching
hospital, and are often due to dangerous heart rhythms.

Heart
attacks must be recognised and treated as quickly as possible
because once a coronary artery is blocked, the heart muscle will die
within four to six hours. Rapid treatment reduces the risk of sudden
death and prevents long-term complications. Don't wait to call for
help - this could make treatment less effective.

If you suspect a heart attack, get medical
help immediately

Everyone's experience is different but common symptoms
include:

chest pain, usually a central, crushing pain, which may travel
into the left arm or up into the neck or jaw, and persists for
more than a few minutes

sometimes the pain doesn't fit this pattern, or is confused
with indigestion

some people having a heart attack don't have any pain

shortness of breath

nausea or vomiting

sweating

feeling light-headed or dizzy

palpitations or an abnormal heart rate

TreatmentWhen a heart attack is suspected, drugs such
as aspirin may be given immediately to improve blood flow through
the coronary arteries. Pain relief, oxygen and other treatments may
also be given.

When a heart attack has been diagnosed, one of
two methods may be used to try to reopen the blocked
artery.

Drugs that dissolve the blood clots blocking the
artery have greatly improved the treatment of heart attacks. These
drugs, known as thrombolytics or 'clot busters', can restore blood
flow in about 60 per cent of cases, although sometimes the artery
blocks again later on.

These drugs aren't suitable for
everyone and there is a risk of bleeding. As many as two per cent of
those treated will have a dangerous brain haemorrhage as a result.
Thrombolytics must be given as soon as possible after symptoms start
and certainly within 12 hours.

The other method is an
operation called percutaneous transluminal coronary angioplasty or
PCI. It involves inserting a tube into the coronary arteries. The
tube carries a deflated balloon that can be inflated in the blocked
area to push against the artery walls and open the vessel. In
general, PCI produces slightly better long-term results than
thrombolytic drugs but it must be carried out in a specialised
centre.

Recovering from a heart attackNot so long
ago, a heart attack meant weeks of bed rest. Nowadays, people may
spend just a few days in hospital, but a much longer process of
rehabilitation is important to help the person recover fully, deal
with common problems such as depression and reduce the risk of a
second attack.